Atomic Radius: Atomic radius of alkali metals increases down the group because on moving down the group, with increase in nuclear charge, number of shells also increases. This results in increase in atomic radius.
lonization Energy: Alkali metals have lowest ionization energy in a period. The ionization energy of alkali metals decreases down the group. Decrease in ionization energy is due to increase in atomic size which results in lesser attraction of electrons by nucleus.
Metallic Character: All alkali metals are strongly electropositive or metallic in nature. Metallic character increases down the group due to decrease in ionization energy down the group.
